Internet Protocol version 6 (IPv6) is the next-generation internetworking protocol version designated as the successor to IPv4. IPv4 is the first implementation used in the Internet and is still widely used. These protocols are used as an Internet Layer protocol for packet-switched internetworks.
IPv6 has a vastly larger address space than IPv4. This results from the use of a 128-bit address, whereas IPv4 uses only 32 bits. This expansion provides flexibility in allocating addresses and routing traffic and eliminates the primary need for network address translation (NAT), which gained widespread deployment as an effort to alleviate IPv4 address exhaustion.
IPv6 provides for a so-called stateless auto-configuration function. The stateless auto-configuration function allows an IPv6 host to auto-generate an IPv6 address based on the subnet information present in router advertisement messages received from the IPv6 routers on the link. These router advertisement messages are periodically multicasted from the router. In order to support IPv6 mobility for mobile nodes (e.g., wireless client devices) in a mobility domain, the network has to ensure a mobile node that has roamed away from its home link, also called its home virtual local area network (VLAN), can receive router advertisement messages sent on its home VLAN, wherever the mobile currently operating. Simply forwarding all the router advertisement messages from the home router to each and every host will result in numerous router advertisement messages being sent over multiple wireless links, placing a burden on the throughput of the wireless links. In addition, some router advertisement messages may need to be suppressed in order to prevent the wireless mobile client device from generating a new IPv6 address and terminating a session.